Angiogenesis (new blood vessel formation) is known to be critical in the development and progression of breast cancer and other solid tumors. Recently the growth factor VEGF (Vascular Endothelial Growth Factor) has been implicated as a crucial growth factor in breast cancer. As such, it represents a reasonable therapeutic target for the treatment of breast cancer. We propose to examine the use of recombinant humanized monoclonal anti-VEGF antibody (rhuMAb VEGF) in a phase II trial conducted in patients with metastatic breast cancer refractory to standard chemotherapy or hormonal therapy, treating patients with weekly infusion of monoclonal antibody. A maximum of 30 patients will be entered into the trial, roughly half of whom will be entered at Indiana University. In addition to standard response evaluation, pharmacokinetic analyses of VEGF and rhuMAb VEGF will be performed, using the services of the GCRC.